Is lifting heavy weight essential for constructing muscle?

There is an ongoing debate about how important heavy weights are to being jacked up, As with most trends, public opinion likes to be grouped around the extremes. Heavy weights are critical one day and completely unnecessary the next day.

Realistically, we need to have a more differentiated discussion about the advantages and disadvantages of hypertrophy approaches with high and low loads. From there we can work out some simple and practical recommendations that can be implemented in our training.

Mechanisms of muscle hypertrophy

Hypertrophy is muscle growth. There are basically three main factors for muscle hypertrophy. Mechanical tension, volume and metabolic load. 1

So far, it has been assumed that muscle damage makes a significant contribution to muscle hypertrophy. Although it can act as a proxy for muscle growth in certain circumstances; Recent research shows that the relationship does not appear to be causally or even reliably correlated. 2

Hypertrophy is observed in overworked individuals who have suffered extensive muscle damage and may still lose LBM (lean body mass). Conversely, there are several cases where an individual experiences minimal muscle soreness with a delayed onset while continuing to build muscle.

I don't think muscle damage should be written off as completely unimportant, but since it's not a direct mechanism, muscle damage isn't covered in depth in this article. My personal point of view is that if you are never sore and not making progress at the same time, you may have to train harder. But beyond that, I don't think it's a metric to reliably base your training decisions on.

Mechanical tension

Under mechanical tension, a muscle is stretched under stress.1 In a study from 2011, it was stated: "It is assumed that mechanical tension disturbs the integrity of the skeletal muscle and causes mechanically transduced molecular and cellular reactions in myofibers and satellite cells." 3

The degree of mechanical tension is dependent on the load and time under tension or the amount of stretch that is exerted on the muscle. Using a combination of these factors, which favors a range where all are optimized, is likely to result in superior hypertrophic adjustments. 3

This sums up the important topic of exercise selection, From a practical point of view, the exercise selected largely determines the stress regulations. For example, dumbbell chest flights require a dramatically different load selection compared to the barbell bench press based on the mechanical differences inherent in each movement

Since volume is one of the main causes of muscle hypertrophy, it is a clear advantage to prefer composite exercises that allow greater volume loading and mechanical tension. 1, 5

Lifting heavy loads not only increases the mechanical tension exerted on the muscles, it also uses high-threshold motor units that would not be accessible at lower intensities.6 These results in some cases have led to an overuse of this approach – too strong Lift often too.

However, since hypertrophy is a complex adaptive response, it is not mediated by a single mechanism. Rather, mechanical tension is simply an aspect of an accompanying matrix that creates muscle growth

The fatigue costs associated with repeated attacks of high intensity resistance training are robust and, if not checked, can lead to overtraining.7, 8, 9

Research shows a significant benefit to mindfully incorporating heavy loads as part of a strength training protocol to maximize hypertrophic response. To prevent overtraining, an effective program design must manage the frequency of high-intensity fights and the associated fatigue.


The volume refers to the number of repetitions multiplied by the number of completed sets (volume = repetitions x sets). As an independent metric, Volume does not offer much insight into the subtleties of a program. The simple reason that the volumes are the same can be a variety of different adaptive responses.

For example, the higher intensities prescribed for person A are more like those of a strength program. The more extensive recipe for Person B is more like a hypertrophy program.

I understand that this is a little too easy, but it is enough to demonstrate my point of view. Both volumes are identical and 24 repetitions were performed in both cases. As I mentioned earlier, the adaptive response is very different in any case.

For this reason, it is common for trainers to use the volume load, which is calculated by multiplying the total number of repetitions by the load.10 The following table shows that volume and relative intensity are the same. Volume load is 20% higher for person A than for person B.

A table of the differences between person A and B.

Research has consistently shown that higher volumes lead to higher hypertrophic gains compared to lower volume interventions.11 This is probably due to a combination of increased muscle tension, metabolic damage and hormonal responses to weight training. 1

A study from 2019 found that "muscle hypertrophy follows a dose-response relationship and that with higher training volumes, greater and greater gains are achieved." 12 Essentially, more volume means larger gains as long as the athlete can recover sufficiently.

This leads to the next point under discussion, the MRV, which is also referred to as the maximum achievable volume. This is a term used by Dr. Mike Israetel was coined to define the maximum amount of volume a person can endure before overtraining.

This is an important concept because, like most things that work well, it is often believed that more is better. However, this dose-response relationship to hypertrophy is mediated by your ability to recover and continue subsequent training sessions of a productive nature. 8

In a 2018 study titled "Effects of Different Intensity of Weight Training with Equal Volume on Muscle Strength and Hypertrophy", it was found that "Leg extension exercises at 30% 1rpm until failure failed the quadriceps muscle volume compared to high intensity exercises (80% 1 rpm) increased in a similar manner) and was superior to a 30% 1RM non-failure condition. "13

This essentially means that the range of intensity in which we can build muscle is much larger than previously thought, around 40-80% 1RM.13 These results also indicate that it is the lowest [resistance training] The intensity (20% 1RM) was suboptimal to maximize muscle adaptation. "13

Although there is a wide range of volumes and intensities that can lead to productive adjustments, it is important to know where these rough limits are and not to unnecessarily venture too far in either direction.

The volume also has an inverse relationship to the intensity.14 ​​This means that the volume necessarily decreases with increasing intensity. This is also the reason why you can squat 10 repetitions at 65%, but only 1 repetition at 100%. This is shown in the graphic below.

GPT chart.

Sometimes I ask myself the question: "If the volume decreases too much, how can you maximize the mechanical tension and the volume at the same time?" This is an excellent question, and while you may not be able to maximize both at the same time, you can get close to optimizing them.

Mechanical tension is not only the raised load, but also the accumulative tension. This means that the extensive training session triggers a significant mechano-transduction even if you don't raise your 1RM as the repetitions and adjustments progress. 1

Metabolic stress

Metabolic stress appears to have a major impact on muscle hypertrophy, either directly or indirectly. An article by Dr. Brad Schoenfeld found that "metabolic stress manifests as a result of physical activity based on anaerobic glycolysis for ATP production, which leads to the later build-up of metabolites such as lactate, hydrogen ions, inorganic phosphate, creatine and others." 1

Lower loads that are raised for high repetitions (15+) may not be sufficient to maximally recruit high-threshold motor units, but can trigger significant metabolic loads.1 Therefore, it seems to be a clear advantage to have higher rep ranges at lower ones Stresses to take advantage of the metabolic stress pathway to hypertrophy.

The practical implementation of low and high intensity protocols varies dramatically. In a study by De Souza et al. From 2018, subjects had to force each group to fail due to the associated cost of fatigue to produce similar hypertrophic, low-stress responses.13 This represents some very real limitations for this type of training.

For example, an isolation exercise such as leg extension to failure will produce a significant hypertrophic response, but the fatigue created will likely be manageable. Compare this to a dumbbell pushed to failure, and the axial load leads to increased systemic fatigue, which can also increase the risk of injury. 15

The fatigue that arises from such a strenuous workout can also affect subsequent workouts and possibly negatively impact downstream performance. In addition, the psychological costs of training at this level are extremely burdensome and should not be sustainable over a longer period. Therefore, when designing a program, the choice of exercises, the order, the waveform and the frequency of implementation should be taken into account.

De Souza and colleagues also found that higher intensities that did not fail are at least as effective to induce a hypertrophic response during exercise.13 This is reflected in the recommendations by Helms et al. For natural bodybuilders, where the training intensities are between 70-80% 1RM make up the largest part of the intensity spectrum used. 16

This in turn comes down to context. When looking at a single sentence, any intensity that led to failure triggers a stronger hypertrophic response than if the sentence did not fail. This is because failure maximizes the combination of stress, volume, and metabolic stress created during the set. 1

However, there is a strong correlation between the occurrence of overtraining when an athlete exceeds their stress / volume thresholds.17 Therefore, training is poorly advised to failure as the primary programming strategy and can lead to injuries and overtraining.

Endocrine response to strength training

Strength training leads to a cascade of endocrine reactions that facilitate the synthesis of muscle mass, There are still some questions about the long-term importance of acute changes in hormones after training. One article found that "a higher total workload in the post-workout recovery phase results in a significantly higher increase in circulating anabolic hormones." 18

Ahtiainen et al. Tried to determine the hormonal response to heavy weight training with the same volume. The only difference in protocol between the control groups was that Group A was instructed to do 4 sets at 12 rpm, where Group B followed the same protocol but could only do 8 repetitions with a weight and the remaining repetitions were forced repetitions ,

After measuring serum testosterone, free testosterone, cortisol, growth hormone and blood lactate; Both groups showed a significant increase in concentration after training.19 However, the forced replication group had a higher concentration than the 12RM group after measurement. There is also evidence that the athlete's exercise age affects the hormonal response to exercise.

One study found that trained subjects showed a lower response to hormone levels (total testosterone, free testosterone, dehydroepiandrosterone, cortisol and sex hormone-binding globulin) after resistance training.20 We can therefore speculate that the endocrine response to resistance training is likely to be weakened over time.20

This could at least partially explain the need for higher volumes in trained athletes to stimulate myogenesis.

Insulin-like growth factor 1 (IGF-1) is a hormone that, together with the growth hormone (GH), promotes normal growth and development of bones and tissue. Although the mechanism by which mechanical stress modulates IGF-1 expression is unclear, there is evidence to support this observation.21

The image below is a visual representation of a dose-response relationship between volume, stress, and endocrine response to weight training (ie, larger stresses and volumes that lead to a greater acute increase). As already mentioned, it is still unclear how acute increases in anabolic hormone concentrations affect long-term results.

However, if the acute increases in the anabolic environment that result from strength training occur frequently enough and to a sufficient extent, it can be assumed that they will be reflected in the downstream profits.

Endocrine response table.

Since there are many speculations as to the relationship between long-term results and acute increases in anabolic hormones, I would not spend much time changing your biochemistry. Just focus on the variables known for muscle growth and let your body take care of the rest.

Training frequency and fatigue management

Each training progress is based on an appropriate recovery, so that subsequent training phases can lead to a positive adaptive response over time. The repeated combat effect is a sports science concept that describes the adaptable response of the body to stress factors that lead to increased elasticity. 22

The speed of our adaptability is limited, and exceeding this limit can lead to injuries and reduced performance.9 Fatigue management is therefore a fundamental part of any effective training protocol. The SRA curve (Stimulus Recovery Adaption) shows the process of adapting to strength training and is shown in the following figure.

Power flow diagram.

Here are three main points. The first is that physical activity creates fatigue, the size of which is determined by several factors, but primarily by volume and load. The second point is that if you wait too long before inserting another training stimulus, an adaptive resolution will occur.

That is, you regress because subsequent training exposures were either insufficiently overloaded, insufficiently frequent, unspecific, or a combination thereof. The third point is when you accumulate fatigue from overloading workouts and your ability to express athletic performance temporarily decreases.

Against this background, the frequency of the training plays an important role for the correct application of various stress strategies, For example, if you do 10×10 squats to fail, you may not be able to exercise your legs for a week. So when you look at the size of the stimulus created in vacuum, it is enormous, which is positive.

But the fact that you can't train for a week probably makes the opportunity cost of this strategy a bad compromise. In most cases, frequencies over once a week are required to really optimize muscle growth. A phased structure and an effective program design can thus help prevent the deterioration of a single signal path, cope with fatigue and also increase future profits.

Practical tips and recommendations

In terms of compound lifts, most of your hypertrophy gains are likely to result from the following recommendations:

Repetitions: 6-15 sets: 4-8 intensity: 60-80% break: 2-3 minutes

However, this does not preclude low-intensity exercise from taking place near or near absolute muscle failure. It simply means that it has to be used intelligently. Since the physiological and psychological fatigue that results from taking sets to absolute muscle failure is also significant and is a terrible experience all round, I would use it in moderation.

Its implementation would probably be most effective for smaller muscle groups or exercises that are limited in the amount of load that can be lifted (e.g., bicep curls, triceps low pressures, calf press, DB shoulder press, etc.).

Implementing a phase structure that highlights certain adaptive paths can be very effective, The ideal structure would be based on each phase potentiating subsequent phases. A possible approach could therefore be a linear periodization model, in which the volume begins high and decreases with time with increasing intensity. An example of this is below:

Phase 1: Metabolism (high volume, low load) Phase 2: Volume (medium volume, medium load) Phase 3: Mechanical tension (medium volume, medium to high load)

Below is an example of a similar workout that has been customized for each phase to give you an idea of ​​what your workout might look like:

Phases of the training table.

As you can see from the sample exercises, each phase can look relatively similar. This brings me to an important point: complex training is not synonymous with effective training. The basics are the foundation of most of your results anyway, and no matter how amazing it would be to find "hacks" that make better progress, it generally doesn't work in practice. It's best to use the full range of repetitions, sets, and intensity ranges while doing most of your work within the guidelines outlined above.

The use of tactics such as giant sets, break sets, supersets, negative sets, etc. can be useful to create metabolic stress. These can be done at your desecration, but I would recommend using them either for machine-based multi-joint exercises or for free-weight isolation exercises or machines. This will help limit the fatigue you can create from this type of workout while creating a significant stimulus,

Hopefully this will remove some of the confusion and provide a practical application for implementing various loading strategies in your hypertrophy program. Lift tall.


1. "The Mechanisms of Muscle Hypertrophy and Their Application", The Journal of Strength & Conditioning Research, LWW.

2. Flann, Kyle L. et al. "Muscle damage and muscle remodeling: no pain, no gain?" The Journal of Experimental Biology, U.S. National Library of Medicine, February 15, 2011.

3. "The use of specialized training techniques to maximize", strength and conditioning journal. LWW.

4. "A biomechanical comparison of traditional squat," the Journal of Strength & Conditioning Research. LWW.

5. Warrior, James. "Single vs. Multiple Resistance Exercises for Muscle Hypertrophy: A Meta-Analysis," Journal of Strength and Conditioning Research, April 1, 2010.

6. "Training-induced changes in neuronal function: training and sports science reviews", LWW.


8. "The fitness fatigue model revised: Implications for …" Strength & Conditioning Journal, LWW.

9. BANISTER, Eric et al. "Dose / Response Effects of Training Modeled from Training: Physical and Biochemical Measures," The Annals of Physiological Anthropology, Japan Society of Physiological Anthropology, February 8, 2008.

10. Schoenfeld, Brad J., et al. "A comparison of volume load increases over 8 weeks of strength training with low or high loads," Asian Journal of Sports Medicine, Kowsar, June 1, 2016.


12. Schoenfeld, Brad J, et al. “Strength training volume improves muscle hypertrophy, but not strength in trained men,” Medicine and Science in Sports and Exercise, Lippincott Williams & Wilkins, January 2019.

13. Lasevicius, Thiago et al. "Effects of different strength training intensities with the same volume load on muscle strength and hypertrophy", European Journal of Sport Science, vol. 18, no. 6, 2018, pp. 772-780.

14. "The Science and Practice of Periodization: A Brief Review: Strength & Conditioning Journal", LWW.

15. "The effect of fatigue on multi-joint kinematics and stress: spine". LWW.

16. Helms, ER, et al. "Recommendations for Preparation for the Natural Bodybuilding Contest: Strength Training and Cardiovascular Training," Journal of Sports Medicine and Physical Fitness, United States National Library of Medicine, March 2015.

17. Foster, Carl. "Monitoring Training in Athletes for Overtraining Syndrome," Medicine and Science in Sports and Exercise, July 1, 1998.

18. Gotshalk, LA, et al. "Multiset Hormonal Responses to Single-Set Heavy Resistance Exercise Protocols," Canadian Journal of Applied Physiology = Canadienne De Physiologie Appliquee, U.S. National Library of Medicine, June 1997.

19. Ahtiainen, Juha P. et al. "Acute hormonal responses to heavy resistance training in strength athletes versus non-athletes," Canadian Journal of Applied Physiology = Revue Canadienne de Physiologie, Appliquee, United States National Library of Medicine, October 2004.

20. "Hormonal responses to resistance training in the long run …", The Journal of Strength & Conditioning Research, LWW.

21. Bamman, MM, et al. "Mechanical stress increases muscle IGF-I and androgen receptor MRNA levels in humans," American Journal of Physiology. Endocrinology and Metabolism, United States National Library of Medicine, March 2001.

22. McHugh, Malachy P. "Recent Advances in Understanding the Repeat Effect: The Protection Effect Against Muscle Damage from a Single Attack of Eccentric Training," Scandinavian Journal of Sports Medicine and Science, US National Library of Medicine, Apr 2003.

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